Synthesis and antibacterial evaluation of novel heterocycles from 5-chloro-3-methyl-1-phenylpyrazole-4-carbaldehyde

Abstract

910-9175-Chloro-3-methyl-1-phenylpyrazole-4-carbaldehyde 1 reacts with acetylpyrone 2 and acetylbenzopyrone 3 via Claisen-Schmidt condensation to afford heterochalcones 4a,b which undergo facile cyclisation with hydrazines to give 3,5-heteroaryl-2-pyrazolines 5a-d in quantitative yield. Further, heterochalcones 4a,b undergo addition reaction using Br2/MeOH in the presence of Pb(NO3)2 or AgNO3 to afford addition products 6a,b. The structures of the newly synthesized compounds have been established on the basis of their spectral studies. The newly synthesized heterochalcones and pyrazolines have been screened for their antibacterial activity against two kinds of strains using the Agar well diffusion method. Some of the compounds showed significant activity against both the strains